Cement or Concrete

This is an extract from the wikipedia entry on cement:

"The name "cement" goes back to the Romans who used the term "opus caementitium" to describe masonry which resembled concrete and was made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick additives which where added to the burnt lime to obtain a hydraulic binder were later referred to as cementum, cimentum, cäment and cement."
To view it in its entirity go to:http://en.wikipedia.org/wiki/Cement

---

and here is some more info on concrete:
[[http://inventors.about.com/library/inventors/blconcrete.htmhttp://inventors.about.com/library/inventors/blconcrete.htm